#include <iostream>
#include <string>
#include <stdlib.h>
using namespace std;

// function prototypes
void initializeNumbers();
// global variable declarations
string numbers;

long long int findProductInNumbers(string numString){
    long long int product = 1;
    int value;
    string num;

    for(int i = 0; i < numString.size(); i++){
        num = numString.substr(i,1);
        value = atoi(num.c_str());
        product *= value;
    }
    return product;
}

long long int findLargestProduct(long long int strLength){

    long long int largestProduct = 0;
    long long int product;
    string numString = "";

    if(strLength > numbers.size() || strLength < 1)
        strLength = numbers.size();

    for(int i = 0; i<=numbers.size()-strLength; i++){
        numString = numbers.substr(i,strLength);
        product = findProductInNumbers(numString);
        if(product>largestProduct)
            largestProduct = product;
    }

    return largestProduct;
}

int main(){

    initializeNumbers();
    cout << findLargestProduct(13) << endl;
    /*for(int i = 0;){

    }*/
    //cout << numbers << endl;
    return 0;
}

void initializeNumbers(){

    numbers  = "73167176531330624919225119674426574742355349194934";
    numbers += "96983520312774506326239578318016984801869478851843";
    numbers += "85861560789112949495459501737958331952853208805511";
    numbers += "12540698747158523863050715693290963295227443043557";
    numbers += "66896648950445244523161731856403098711121722383113";
    numbers += "62229893423380308135336276614282806444486645238749";
    numbers += "30358907296290491560440772390713810515859307960866";
    numbers += "70172427121883998797908792274921901699720888093776";
    numbers += "65727333001053367881220235421809751254540594752243";
    numbers += "52584907711670556013604839586446706324415722155397";
    numbers += "53697817977846174064955149290862569321978468622482";
    numbers += "83972241375657056057490261407972968652414535100474";
    numbers += "82166370484403199890008895243450658541227588666881";
    numbers += "16427171479924442928230863465674813919123162824586";
    numbers += "17866458359124566529476545682848912883142607690042";
    numbers += "24219022671055626321111109370544217506941658960408";
    numbers += "07198403850962455444362981230987879927244284909188";
    numbers += "84580156166097919133875499200524063689912560717606";
    numbers += "05886116467109405077541002256983155200055935729725";
    numbers += "71636269561882670428252483600823257530420752963450";
}
